Various smoke barrier systems often contain a barrier in a housing with a door, and the door is movable between at least two positions. For example, a drop-down smoke curtain can be contained in a housing above a doorway. The curtain can be configured to drop down through an opening in the bottom of the housing to cover doorways, for example, during a fire. The curtains, when deployed, prevent smoke or fire from passing through the doorway. When the curtain is stored in the housing, it can be desirable to cover the opening in the bottom of the housing with one or more movable doors. For example, it can be desirable to cover the opening for aesthetic purposes, to prevent unwanted foreign objects from being placed in the housing, to prevent tampering with the curtain assembly, or to prevent unauthorized access into the housing. When one or more doors are used to cover the housing's bottom opening, the doors must not interfere with deployment of the curtain to cover the doorway.